Agree with using less voltage to supply R2 R4. I think 5V is even better.
Let us know your experience with the new rev3 QDX regarding the T1 and R2 R4 issues.
Good luck.
73 de YO3FFF
Cristi
Pe mar?i, 14 iunie 2022, 21:19:40 EEST, Evan Hand <elhandjr@...> a scris:
On Tue, Jun 14, 2022, at 12:22 PM, cris blak wrote:
Have you measure the R2 R4 temperature at 9V after a WSPR 2min transmission? How was it comparing with 12V?
Hi Cristi
I built my rev 1 QDX for 12volts.? I had multiple failures of the output MOSFETs and IC5.? Some were software issues (the version of the software shipped on the Rev 1 was known to have a possible problem that I did experience), and one was self-induced while probing for signals.? The others were due to antenna SWR.issues.
I do not have an IR camera to take measurements.? I used the touch test and did not see an excessive heat issue,??
I plan to build my rev 3 QDX with the other build club members because of the current measurements across R2 and R4.? My analysis is that those two resistors will do better at the 9volt level as the circuit was initially designed to handle.
